A shows a high magnification microscopy microphotography of VL PAG. B and B' show the western blot analysis and relative quantification of EP1 receptor protein levels within the VL PAG in sham and SNI rats. C shows the double staining quantification for GABA vesicular transporter (VGAT) and glutamate vesicular transporter (VGluT) with EP1 receptor. The merge in C' indicates the co-localization of EP1 (red) and VGAT (green) labelled profiles. The arrow in the upper panel represents a positive EP1 profile which is not counterstained with VGAT, while the asterisks represent the double positive labelling EP1/VGAT. The lower panel shows the double staining for vesicular glutamate transporter VGluT1 (green) and EP1 receptor (red). The merge indicates the extremely scarce presence of EP1 in the VGluT1 labelled glutamatergic neuron, as highlighted by the arrows. Data represent mean ± S.E.M., n = 6 rats per group. Scale bars = 50 μm.